Flow distribution channels to control flow in process channels

Abstract

The invention describes features that can be used to control flow to an array of microchannels. The invention also describes methods in which a process stream is distributed to plural microchannels.

We claim: 
     
       1. A method of fluid processing, comprising:
 passing a process stream into a manifold; 
 wherein the manifold is connected to at least a first flow distribution channel (FDC) and a second FDC; 
 wherein each FDC comprises a series of turns, comprising at least four turns that are 90° or less, or comprising at least two turns that are greater than 90°; and 
 wherein the first FDC channel connects the manifold to a first process channel; 
 wherein the second FDC channel connects the manifold to a second process channel; 
 and wherein the portion of the process stream that flows through the first FDC connects with only one process channel and does not connect with any other FDC so that all of the portion of the process stream that enters the first FDC flows into the first process channel; wherein the pressure drop through the first FDC is at least 2 times greater than the pressure drop through the first process channel that is connected to the first FDC; and 
 conducting a unit operation in the first and second process channels; and wherein the unit operation in the first process channel comprises partially boiling a liquid as it passes through the first process channel; and wherein the first and second process channels have at least one internal dimension of 1 cm or less; and 
 wherein the first process channel is one of at least 10 parallel process channels connected to the manifold; and 
 wherein flow through the at least 10 parallel process channels is characterized by a flow distribution that varies by 10% or less in the absolute overall quality index factor when the flow is turned down by 50%, wherein overall quality index factor=Q=(M max −M min )/M max *100, wherein M max  is maximum mass flow rate in a parallel process channel connected to the manifold and M min  is minimum mass flow rate in a parallel process channel connected to the manifold. 
 
     
     
       2. The method of  claim 1  wherein each FDC comprises at least three turns and each of said three turns has an angle of at least 135°. 
     
     
       3. The method of  claim 1  where 0.5 to 50% of the process stream entering the first process channel undergoes boiling in the first process channel. 
     
     
       4. The method of  claim 1  wherein flow in the first FDC is Newtonian and wherein flow in the first process channel is non-Newtonian. 
     
     
       5. The method of  claim 1  wherein the first and second FDCs have the same length. 
     
     
       6. The method of  claim 1  wherein the first FDC has a cross-sectional area and the cross-sectional area of the first FDC at all points is less than the cross-sectional area of the first process channel. 
     
     
       7. The method of  claim 6  wherein the first FDC channel is on the same plane as the first process channel and the manifold. 
     
     
       8. The method of  claim 1  wherein the first process channel has a length that is at least twice as long as the distance from the manifold to the first process channel; and wherein the second process channel has a length that is at least twice as long as the distance from the manifold to the second process channel. 
     
     
       9. The method of  claim 8  wherein the first process channel has a length that is at least ten times greater than the distance from the manifold to the first process channel;
 and wherein the second process channel has a length that is at least ten times greater than the distance from the manifold to the second process channel. 
 
     
     
       10. The method of  claim 1  wherein the first and second FDCs have a serpentine shape. 
     
     
       11. The method of  claim 1  wherein the first FDC comprises a first cross-sectional area and the first process channel comprises a second cross-sectional area, and wherein the first cross-sectional area is at least 2 times smaller than the second cross-sectional area. 
     
     
       12. The method of  claim 1 , wherein the device is made up of a plurality of laminae and the first FDC has a three dimensionally tortuous path through multiple layers. 
     
     
       13. The method of  claim 1  wherein each of the at least 10 parallel process channels are connected to the manifold via flow distribution channels and wherein each flow distribution channel has serpentine turns. 
     
     
       14. The method of  claim 1  wherein each flow distribution channel forms a direct connection between the manifold and a process channel. 
     
     
       15. The method of  claim 1  wherein each flow distribution channel forms a direct connection between the manifold and a process channel. 
     
     
       16. A method of fluid processing, comprising:
 passing a process stream into a manifold; 
 wherein the manifold is connected to at least a first flow distribution channel (FDC) and a second FDC; 
 wherein each FDC comprises a series of turns, comprising at least four turns that are 90° or less, or comprising at least two turns that are greater than 90°; and 
 wherein the first FDC channel connects the manifold to a first process channel; 
 wherein the second FDC channel connects the manifold to a second process channel; 
 and wherein the portion of the process stream that flows through the first FDC connects with only one process channel and does not connect with any other FDC so that all of the portion of the process stream that enters the first FDC flows into the first process channel; wherein the pressure drop through the first FDC is at least 2 times greater than the pressure drop through the first process channel that is connected to the first FDC; and 
 conducting a unit operation in the first and second process channels; and 
 wherein the unit operation in the first process channel comprises partially boiling a liquid as it passes through the first process channel; 
 and wherein the first and second process channels have at least one internal dimension of 1 cm or less; and wherein the first process channel is one of at least 10 parallel process channels connected to the manifold; and 
 wherein flow through the at least 10 parallel process channels is characterized by a flow distribution that varies by 10% or less in the absolute overall quality index factor when the flow is turned up by 20%, wherein overall quality index factor=Q=(M max −M min )/M max *100, wherein M max  is maximum mass flow rate in a parallel process channel connected to the manifold and M min  is minimum mass flow rate in a parallel process channel connected to the manifold. 
 
     
     
       17. The method of  claim 16  where 0.5 to 50% of the process stream entering the first process channel undergoes boiling in the first process channel. 
     
     
       18. The method of  claim 16  wherein the first FDC has a cross-sectional area and the cross-sectional area of the first FDC at all points is less than the cross-sectional area of the first process channel. 
     
     
       19. The method of  claim 18  wherein the first FDC channel is on the same plane as the first process channel and the manifold.